Aircraft: C172
Phase of flight: Descent
Anomaly: ATC Issue All Types; Aircraft Equipment Problem Less Severe; Airspace Violation All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Taxiway

Entering Bravo airspace without clearance and crossing taxi hold line without ground clearance.This was my first 2 hour cross-country out of state since earning my license a few months ago. I spent several nights flight planning and discussed the route with two other pilots. After Takeoff; opened my flight plan; contacted local Bravo approach for transition and requested Flight Following. Transitioned the Bravo without incident; and was on flight following. Trip duration was 2.5 hours at 115kts. Several handoffs from FF; including military approach; all successful. About 50 miles from destination I lost GPS signal; and every time I tried to pull up the electronic chart; it would default to the equator. Since I knew if I stayed on course the airport was on the other side of the Ridge some 30+ minutes away; and I was on FF if I needed help and the final handoff would mean I was about 20 minutes away. I stopped trying to get the GPS signal back and setup the electronic chart just as a chart. Shortly after losing GPS; FF stated the automatic handoff was not working and FF is now canceled and return to own VFR navigation. Now I start to get pretty nervous; and I start to monitor ATIS. I see one of my waypoints to the right; and ATIS gets picked up. Once I have ATIS I call the Tower; still do not see the ridge (airport is on the other side of the ridge) and report I am some 30+ miles out. They say to report when I am closer. Getting more nervous I see the ridge and start my descent from 8;500 to below 8000. I call Tower again and report I'm xx miles from the airport; they reply that I must be too low because they do not see me on radar. Slowly descending but not too much so I have proper terrain avoidance over the ridge but more nervous because I start to question my Altimeter because Tower just told me I was too low. I call Tower and tell them I can't be too low because I am at 8;500. I was already below 8;000 but reported where I was just 2 minutes ago which was 8;500. They go on to tell me I am in the Bravo without clearance; and still not on radar. Now I busted Bravo; Tower is telling me I am too low; the ridge is fast approaching at 5;500; FF dropped me 10 minutes ago and GPS is down. I get over the ridge; I don't remember my altitude at this point; but I don't think I was in the Bravo because I was able to get to traffic pattern altitude pretty quickly after going over the ridge. Tower has me circle twice then cleared for RW 17L. I enter left base; wide turn to final for 17L; over 17L (too high) Tower yells at me that I was cleared for 17L. I think he means I am over the taxiway or on the wrong RW so I go around. Very high anxiety at this point; I'm told to make left traffic; which I do and land without incident. Tower tells me to turn on E; stay on this frequency and stop between the runways. I do; he gives me a number; then tells me to cross runway 17R and contact ground. I cross the RW; the taxiway is right in front of me and parking is just a few feet away; I turn to my left and see a plane taxing towards me so I full throttle to get out of the runway environment. At that moment I questioned the instructions from tower; I must have heard them wrong; the safest thing was not to be where I was. I'm out of the RW environment; Tower continues to rightfully yell at me; I struggle to change radios but finally get a hold of ground where they say parking is to my left.I depart that airport a few hours later and return home via several Bravo/Military transitions without incident. Once home; I spend the next hour going through everything to find out what I did wrong and how it could have been avoided. (1) I should have planned on going around the Ridge; since the bottom shelf of the Bravo and the top of the Ridge were too close for my experience level. (2) Needed to trust my Altimeter because it was properly updated the entire trip and could not be off as much as I started to think. (3) Do not rely on the GPS; I may not have known the exact miles or minutes from the airport but I knew the direction and final way point. (4) Stopping before the taxiway would have been a safe; and correct choice as well. The next day I attended a FAAST seminar; contacted my CFI for some additional ground discussion and practice flight training on entering the airport environment from a high altitude with Bravo transitions. I don't think I busted the Bravo; and as far as I know I was never on radar because I was too low. I'm also reviewing airport signs and procedures since not stopping short of the hold line Taxiway and contacting ground was my biggest concern. C172 pilot reported losing GPS during a two hour cross country flight to HND from Southern California. The location of HND was never in question; but the ability to avoid LAS Class B was and the reporter was advised that he was in Class B based on his position report. The first approach resulted in a go-around and the second in a landing with a taxiway incursion after clearing the runway.